oils and oil's

[Compass790]

Switched my Toyota to synthetic 5w-40 after 200,000k's because i wanted long drain interval. No problems, now after 300,000 km & uses less oil. BUT this is a petrol engine, havent done it on diesel.

[dkenny64]

I wonder why it ran hotter?
I run 35 psi, before I changed my turbo..the new one is still limited to 22psi..waste gate.
the old its was disabled..the new will be soon.
its never run hot..towing or not..I tow all the time but about 5k lbs..so not a heavy load
I do miss the 35psi boost..
yes the boat diesel are a little different..4-108 like my 4-154 don't have a turbo..
with that in mind..one of the big advantages of synthetic is the resistance to coking in the turbo bearings..is gone..

-dkenny

[a64pilot]

By hotter, I mean coolant temp hotter than my boat, boat is 180 I think, truck was 195.
Plus as you say, the turbo being oil lubricated dumps a lot of heat into the oil, unless maybe it's a water cooled turbo, I think the Duramax was.
I still idled until pyrometer was under 200 though.

[iancoombe]

Originally Posted by Guy

I wish people would stop saying that, it ain't "as new". If you actually did the "ovhl" per the manual, most parts would be just within limits, not "as new". The decent ovhl of a Perkins for example is new liners, new pistons, rings, new exh valves, rod and main bearings. The oil pump is probably fine. There are dozens of other things you could inspect but people don't. Not to mention rebuilt fuel pumps, injectors, starters, coolers, waterpumps etc.

I ask for advice and that's your contribution, really!

[Wotname]

Originally Posted by a64pilot

OK on an aircraft engine I overhaul I fill it with oil and run it for 10 or 15 min and then drain the oil and cut open the filter to inspect for metal.
Reason is vast majority of break in, wear in or whatever you call it occurs very fast and 99% of the metal particles come off really, really quick, and I want that stuff out of the motor, and just in case there may be any glass from bead blasting or dirt from assembly etc., I want it out, and oil is cheap.
Then say 10 hours on the next change, next one on schedule, again oil is cheap and I don't want that metal circulating around my engine, yes the filter catches a lot, but some fine stuff gets through.

Now here is the hard part, run it easy for the first hour say, but after that you want to run it hard, maybe start out by hard for a few minutes then back off a while then hard again etc.
Reason for that is to seat the rings, run it easy and they may never seat and you will have an engine that is forever a little down on compression and always burns some oil.

Opinions on engine break in will vary as much as which anchor to use.

Forget the stuff about which oil and additives etc, but read this, an engine is an engine to a great extent
https://www.lycoming.com/content/har...t-engine-break

Hard to argue against the logic

As an aside, I note many aero oils are called "ashless dispersant", is this another name for synthetic or something else again?

[Stu Jackson]

Universal M25, now 3200 hours, switched to synthetic at 1500, started seeing signs of weeping around the oil pan, switched back to dino, no problems since. Why spend twice as much? I never get it when this question keeps coming up.

[model 10]

Originally Posted by Wotname

As an aside, I note many aero oils are called "ashless dispersant", is this another name for synthetic or something else again?

It's a "fully compounded" mineral oil that keeps particles in suspension.